A new technique for the selective dissection of animal tissues for scanning electron microscopy (SEM) depends on overosmication (24 or more hours in OsO4), dehydration to 100% acetone and subsequent sonication at 80 kHz. This technique has been demonstrated to be satisfactory on all tissues thus far tried. Collagen containing tissues (notably basal laminas) are most resistant to the vibratory insult but other tissues can be selectively dissected. The technique is expecially useful for the SEM demonstration of the microcirculation. Variants of vibratory cycles per second (Hertzian values), vibratory forces and prefixation techniques will be systematically investigated with the aim of demonstrating fine structure (selectively visualized) to the greatest possible advantage in SEM.